The subject invention relates to helicopters and particularly a helicopter blade assembly adapted to be used in a helicopter and the method of manufacturing such a blade.
Helicopter blades have been one of the weaknesses of helicopter construction since the inception of the helicopter. The blades need to be lightweight and also need to maintain a desired shape and position. Conventionally blades are made from aluminum. Aluminum blades, however, have been difficult to maintain, particularly in areas where the blades are touched by people or objects. Aluminum blades are very easily dinged or misshapen from an ideal condition. Each variation from the desired shape causes potential vibration, ride discomfort and possible control problems with the helicopter in varying degrees.
Aluminum blades are also relatively more expensive than needed because of manufacturing techniques used to cant the blade to develop a twist in the blade so that a working area of the blade is isolated as a forced wing and the rest of the blade is stalled. Furthermore, the manufacturing technique places stresses on the blade that may affect the functionality of the blade.
Accordingly, there exists a need for a lightweight, yet durable helicopter blade that can also integrate the blade twist needed without stressing the blade in any significant manner. This need also must be accomplished in varying lengths to accommodate various types of helicopters and conditions of operation, as well as be relatively inexpensive to manufacture. More specifically, there is a need for a helicopter blade assembly that may be manufactured from a very small number of molding tools, thereby significantly reducing the cost of manufacturing and increasing the ease of assembly.
The present invention is a helicopter blade assembly for use on a helicopter. The assembly is a unitary panel when finally constructed, and can take impacts and even breakage while maintaining structural integrity. The blade can be designed with any twist desired without stressing the blade since the twist is set into the components prior to assembly.
The present invention provides a helicopter blade assembly that is relatively inexpensive to manufacture and can be constructed to a wide variety of specific lengths and designs without significant changes in assembly procedures beyond a different mold construction. Few molding tools are needed to manufacture the invention, resulting in reduced costs to the manufacturer and proportional cost reductions to the consumer.
The assembly process is also easier to pursue than the creation of a conventional blade since it includes a step with expanding foam that creates the final product from the inside of the blade and fills in any potential areas of void or weakness, as well as integrating the various components into a solid element of layers which remains integral even if all or a portion of one layer is damaged or removed, such as in the situation of impact with the blade, so that the helicopter can still fly in a controllable manner after the occurrence of such a condition.